The Ninth Circuit has voted to grant the petition for rehearing in United States v. Seljan, a case that considers how the Fourth Amendment's border search exception applies to the search of a FedEx package sent from California to the Phillipines. In the original panel opinion, Judges Gould and Clifton applied prior Ninth Circuit precedent and found that the search need not be based on reasonable suspicion so long as it was "reasonable" based on "the scope of the intrusion, the manner of its conduct, and the justification for its initiation." In a partial concurrence and partial dissent, Judge Pregerson argued that such searches such require reasonable suspicion.

This one will be interesting to watch because the Ninth Circuit's border search cases can be rather out-of-step with U.S. Supreme Court precedent. As I explained in this post in 2005, "In recent years, the Justice Department, the Ninth Circuit, and the Supreme Court have been involved in a bit of a tug-of-war over the rules that should govern invasive car searches at the Mexico border." The big question in these cases, and in border search cases more broadly, is whether to require reasonable suspicion before a border search can occur. The U.S. Supreme Court's cases suggest the answer is no, see, e.g., Flores-Montano and Ramsey, but the Ninth Circuit's cases are much more friendly to a "yes" answer. Given the rehearing in Seljan, it will be interesting to see if the Court ends up bringing its precedents more in line with the Supreme Court's or takes a different view.

The issue is whether the border search exception includes being able to read people's mail. I hadn't been aware previously that the border search exception extended to reading mail. Interesting case. From the dissent:
I do not believe that the Fourth Amendment
permits federal customs inspectors acting without reasonable
suspicion to read what is obviously a person's letters or
papers merely because the inspector finds those items in a
package destined to cross the U.S. international border.
The Fourth Amendment protects "the right of the people to
be secure in their persons, houses, papers, and effects." U.S. Const. amend. IV (emphasis added). The border search doctrine is a narrow exception the Fourth Amendment prohibition against warrantless searches without probable cause." United States v. Sutter, 340 F.3d 1022, 1025 (9th Cir. 2003). However, although "the expectation of privacy is less at the border than it is in the interior," United States v. Flores-Montano, 541 U.S. 149, 154 (2004), privacy is not extinguished entirely.
Any rule allowing government officials to read private
papers without individualized suspicion risks serious intrusions on privacy.

...it will be interesting to see if the Court ends up bringing its precedents more in line with the Supreme Court's or takes a different view.

Is this a serious question?

Presumably the Ninth can't issue a precedent that conflicts with the Supremes. But they could attempt to distinguish similar cases from existing SCOTUS precedent and then rule in a way that is different from the spirit of the high court's rulings while not violating the letter.

Since the Supremes hear so few cases it's inevitable that there will be areas where the Appeals Courts are more or less in conflict and yet do not get over ruled.